Voltage controlled oscillators (VCOs) are an important and integral part of many electronics systems. VCO applications include carrier synthesis in cellular phones, phase locked loops in microprocessors and communication systems, and clock generations for optical communications. Although VCOs have been used in numerous electronic systems for more than a hundred years, none of the known architectures satisfy all of the following requirements: (i) providing a frequency of oscillation that is independent of semiconductor process corners, (ii) providing a frequency of oscillation that is independent of temperature, (iii) providing an amplitude of oscillation that is independent of semiconductor process corners, (iv) providing an amplitude of oscillation that is independent of temperature, and (v) providing an amplitude of oscillation that is independent of tuning or oscillation frequency. Because these requirements have not been met, the VCO amplitude and frequency varies in an undesirable fashion.
Accordingly, there is a need in the art for improved architectures.